Grizzly and screen for grading materials



W. ROSS Sept. 15, 1931.

GRIZZLY AND SCREEN FOR GRADING MATERIALS Fiied Ma 29, 1928 4 Sheets-Sheet l w. R085 I 1,823,126

GRIZZLY AND SCREEN FOR GRADING MATERIALS Filed May 29. 1923 4 Sheets-Sheet 2 W. ROSS Sept. 15, 1931.

Filed May 29, 1928 4 Sheets-Sheet 3 W. ROSS Sept. 15, 1931.

GRIZZLY AND SCREEN FOR GRADING MATERIALS Filed May 29, 192 8 4 Sheets-Sheet 4 Patented Sept. 15, 1931 PATENT QFFICE WILLIAM BOSS, 013 SUR-BITON, ENGLAND GRIZZLY AND SCREEN FOR GRADING MATERIALS Application filed May 29, 1928, Serial No. 281,542, and in Great Britain June 25, 1927.

This invention relates to screens for grading materials and particularly to what are commonly known as grizzlies and screens such as are described, for example, in the specifications of my British Letters Patent Nos. 1232-01 and 179562 and which in general comprise two sets of bars supported substantially horizontally and arranged to move in closed orbits of different lengths, which orbits, however, coincide in the screening zone in which the said bars will be separated by spaces of predetermined size. With the divergence of the orbits after passing the screening zone the spaces between the bars should be automatically increased in size and attain a maximum size when the bars are traversing the sections of their orbits directly beneath the screening zone whereby lines which pass between the bars in the screening zone are passed freely through the spaces between said bars when traversing the lower or return portions of their orbits.

lVith such screening arrangements it is found in general that pieces of over-size material and particularly slabby pieces which become wedged between the bars in the screening zone are carried round and rearwards past the over-size discharge point and into the under-size zone, this defect being due to the slowness of the divergence of the bars between which the slab is wedged and also in the case of the drop link typeof grizzly described in British specification No. 123201 to the fact that the drop bars swing round and knock over-sized pieces rearwards into the under-sized compartment.

The object of the present invention is to provide an improved construction which shall be free from the defects and disadvantages above noted, and the invention consists in a grizzly or screen of the type referred to having means whereby each aperture between the bars is suddenly and substantially enlarged when it arrives at the over-sized discharge point.

The invention also consists in a grizzly or screen of the type referred to having means for supporting the screen bars whereby they are free to move forward individually for the purpose of enlarging the space or aperture between them when arriving at the oversized discharge point. i

The invention also consists in other details and arrangements hereinafter described or indicated.

The accompanying drawings illustrate one convenient mode of carrying out the invention.

Figure l is a general sectional elevation showing the type of apparatus to which the invention is applied and Figure 2 is an end elevation partly in section.

Figure 3 is a part sectional plan of one convenient form of apparatus in accordance with the invention Figure 4 is a sectional elevation of a part shown in Figure 3.

Figure 5 is a sectional plan view of a modification;

Figure 6 is a sectional elevation of Figure 5; 4

Figure 7 is a part sectional plan of a further modification;

Figure 8 is a sectional elevation of a part shown in Figure 7 Figure 9 is a sectional plan of a still further modification Figure 10 is a sectional elevation of a part shown in Figure 9;

Figure 11 is a part sectional plan View of a still further modification, and

Figure 12 is a sectional elevation of a part of Figure 11.

In carrying my invention into effect in one of its simplest forms I provide in the main belts carrying the bars enlarged sockets which permit each bar an amount of individual movement so that after emerging from the screening zone and'upon reaching the over-sized discharge point each successive bar moves in its socket to enlargethe aperture to the rear thereof, the arrangement in general being such that in the screening zone the bars will be in rearward or inward position relativeto the socket'and to the orbit, while upon reaching the discharge point each bar will move to a more forward or outward position, thus increasing the space at its rear.

In the specific embodiment of the invention illustrated in Figures 3 and 4 in its application to the drop bar type of grizzly or screen as described in British specification No. 123201 and in which the main bars are car ried in chains I provide an elongated or oval hole a in the chain link carrying the main bar I) so that in this way such main bar is freely socketed in the chain and in the screening zone the bar will be at the rear of the hole a but when the discharge point is reached it will advance to the forward part of the hole.

In each of the chain links a supporting a drop bar d I also provide an elongated or oval hole 6 in which is freely socketed an extension hub of the chain 7, it being obvious that the drop bar will also occupy rearward and forward positions in the same manner as the main bars while in the screening zone the drop bar is supported by the bolt head 9 engaging a projection 9 upon the link 0.

When applying the invention to the drop bar type of grizzly or screen in which the main bars are carried in rotating discs instead of chains, I provide upon the discs 7L (Figures 5 and 6) elongated holes and protruding hubs similar to those herein described with reference to the chains, and the drop bars would be supported upon their links by bolt heads 9 protruding from the discs or by a flange or the like cast on the discs or attached thereto. In a modification of the invention designed to dispense with oval holes and as illustrated in Figures 7 and 8 I may provide eccentric trunnion ends i upon the bars (Z and mount them eccentrically in the sockets in the chains, the bars in the screening zone being supported at y in rearward relation to the journals.

In a further modification of the invention which also disposes with oval or elongated holes and as illustrated in Figures 9 and 10 I mount tubes is over the bars, the bore of the tubes being larger than the diameter of the bar and the tubes being supported in the screening zone in rearward relation to the bars.

In a still further modification I may, instead of having sockets on the chain belts, make the bars with socketed ends Z and mount them on pins m projecting from the chain belts, the modifications hereinbefore described being applicable equally to the types of screens or grizzly described in both of the British specifications hereinbefore referred to.

The invention is not to be limited to the details of construction which are hereinbefore given by way of example since I may employ any suitable means for enlarging the space or aperture between bars when the same arrive at the over-size discharge point and I may vary the actual construction of grizzly or screen and the arrangement of chutes or other divisions or partitions in association therewith depending upon the nature of the materials to be graded or any practical requirements that may have to be fulfilled.

I claim:

1. A grizzly or screen comprising endless chains, bars supported by said chains and bars pivoted to said chains, the ends of said first-mentioned bars being eccentrically located in apertures in said chains.

2. A grizzly or screen comprising endless chains, bars supported by said chains and bars pivoted to said chains, and means Whereby said first-mentioned bars are caused to move individually relative to the chains in the direction of motion thereof, each of said second-mentioned bars being pivoted and adapted to rotate about one of the first-mentioned bars and movable relative thereto at right angles to the arc of rotation.

3. A grizzly or screen comprising endless chains, bars supported by said chains and bars pivoted to said chains, the ends of said first-mentioned bars being eccentrically located in apertures in said chains and said pivoted bars being adapted to move linearly with respect to the first-mentioned bars.

4. A grizzly or screen comprising movable supporting members having a plurality of apertures, bars carried by said members whose ends are eccentrically located in said apertures, hub members on the supporting members, links eccentrically pivoted on the hub members and bars carried by said links.

5. A grizzly or screen comprising a pair of endless chains having apertures and a plurality of bars horizontally supported thereby, the ends of certain of said bars being eccentrically located in said apertures, a plurality of link members attached to said chains and carrying the remainder of said bars, said links being adapted to rotate about and move linearly with respect to the eccentrically located bars.

6. A grizzly or screen comprising a pair of spaced endless chains having ellipticallyshaped apertures and hub members equally spaced along the length thereof, a plurality of bars whose ends are located in said apertures, a plurality of rotatable links eccentrically mounted on said hub members, and a plurality of bars carried by said links.

7. A grizzly or screen according to claim 5 having stop members on said chains adapted to prevent rotation of the link members in one direction relative the eccentrically mounted bars.

8. A grizzly or screen according to claim 6 having lugs on said chains projecting into the path of rotation of said links.

In testimony whereof I have signed my name to this specification. 

